1. Technical Field
The present invention relates to inspection and review systems to detect and analyze defects in manufactured substrates.
2. Description of the Background Art
Inspection processes are used at various steps during a semiconductor manufacturing process to detect defects on wafers and reticles. As the dimensions of semiconductor devices decrease, detection of defects of decreasing size has become necessary since even relatively small defects may cause unwanted aberrations in the semiconductor devices. The inspection process typically only involves detecting defects on the wafer or reticle and providing limited information about the defects such as location on the wafer or reticle, number of defects on the wafer or reticle, and sometimes defect size.
Defect review is often used to determine more information about individual defects than that which can be determined from inspection results. For instance, a defect review tool may be used to revisit defects detected on a wafer or reticle and to examine the defects further. Defect review typically involves generating additional information about defects at a higher resolution using either a high magnification optical system or a scanning electron microscope (SEM).
Some defects may be selected as candidates for sub-surface review. Sub-surface review generally involves manually navigating to the location of a selected defect, manually cutting the wafer or reticle to obtain a cross section, and high-resolution imaging of the cross section. The cut angle is usually determined based on a recommendation by a person who is familiar with the selected defect.
It is highly desirable to improve inspection and review systems to detect and analyze defects in manufactured substrates.